3-substituted pyridine compounds and derivatives thereof

ABSTRACT

Herbicidal 3-substituted pyridine compounds and derivatives thereof of the formula: ##STR1## wherein Ar is a substituted or unsubstituted 5- or 6-membered heteroaryl group having 1, 2 or 3 ring nitrogen atoms with the remainder of the ring atoms being carbon; a substituted or unsubstituted 5-membered heteroaryl group having a ring heteroatom of oxygen or sulfur with the remainder of the ring atoms being carbon; or a substituted or unsubstituted 5-membered heteroaryl group having one ring nitrogen atom and either an oxygen or sulfur ring heteroatom with the remainder of the ring atoms being carbon. Herbicidal compositions containing such 3-substituted pyridine compounds and derivatives thereof and methods of controlling undesirable vegetation employing these compounds and derivatives are also disclosed. The compounds in which XR is hydroxyl are also useful as intermediates for producing the disclosed 3-substituted pyridine derivatives.

This application is a divisional of application Ser. No. 08/236,831,filed May 2, 1994.

FIELD OF THE INVENTION

In one aspect, this invention relates to novel 3-substituted pyridinecompounds and derivatives thereof which exhibit unexpectedly desirableherbicidal activity. In other aspects, this invention relates toherbicidal compositions comprising a 3-substituted pyridine compound orderivative thereof and a suitable carrier, to a method of controllingundesirable vegetation comprising applying to the area where control isdesired an herbicidally effective amount of a 3-substituted pyridinecompound or derivative thereof and to intermediates useful in makingsuch compounds.

BACKGROUND OF THE INVENTION

The need for effective herbicides needs no special emphasis. The controlof weeds and undesirable vegetation is of great economic importancesince weed competition inhibits the production of foliage, fruit or seedof agricultural crops. The presence of weeds can reduce harvestingefficiency and the quality of the harvested crop. Weeds on noncroppedareas may cause a fire hazard, undesirable drifting of sand or snow,and/or irritation to persons with allergies. Thus, suppression ofundesirable weed growth is very advantageous.

Accordingly, it is an object of this invention to provide effectivenovel herbicidal compounds, as well as to provide novel herbicidalcompositions and novel methods of controlling weeds. Further, it is anobject of this invention to provide intermediates which, as well asexhibiting herbicidal activity, are also useful in the production ofother herbicidally active compounds.

While certain hydroxybenzyl-substituted nitrogen-containing heteroarylcompounds are disclosed in the art, these disclosures contain nodescription of the utility of such compounds. Thus, Radinov et al.,"Synthesis of 4-Amino-3-pyridinyl and 4-Amino-5-pyrimidinyl Aryl Ketonesand Related Compounds via an ortho-Lithiation Reaction", Synthesis, pp.886-891 (November 1986), disclose inter alia at page 887, compounds ofthe formula ##STR2## wherein A is CH or N, and when A is CH, X¹ is H andX² is hydrogen, chlorine or fluorine, and when A is N, X¹ is chlorineand X² is hydrogen.

Somewhat similarly, Marsais et al., "Directed Lithiation of4-Halopyridines: Chemoselectivity, Regioselectivity and Application toSynthesis", J. Heterocyclic Chem., Vol 25, pp. 81-87 (1987), disclosethe production of compounds of the formula ##STR3## wherein El is phenylor 2-methoxyphenyl.

Certain (non-substituted)-pyridyl-3-carbinols of the formula ##STR4##are disclosed in U.S. Pat. No. 4,407,806 to Cherpeck (wherein R and R¹are as defined therein).

Similarly, U.S. Pat. No. 4,116,665 to Krumkalns discloses a method ofregulating the growth of aquatic weeds employing compounds of theformula ##STR5## wherein, inter alia, R¹ may be hydrogen, R² may be(substituted)-phenyl and X may be hydroxyl or alkoxy.

Further, commonly owned U.S. Pat. No. 5,308,826, describes herbicidal4-substituted pyridyl-3-carbinols.

SUMMARY OF THE INVENTION

In one aspect, this invention is directed to a compound of the formula(I): ##STR6## wherein:

Ar is a substituted or unsubstituted 5- or 6-membered heteroaryl grouphaving 1, 2 or 3 ring nitrogen atoms with the remainder of the ringatoms being carbon; a substituted or unsubstituted 5-membered heteroarylgroup having a ring heteroatom of oxygen or sulfur with the remainder ofthe ring atoms being carbon; or a substituted or unsubstituted5-membered heteroaryl group having one ring nitrogen atom and either anoxygen or sulfur ring heteroatom with the remainder of the ring atomsbeing carbon;

R¹, R², R³ and R⁴ are each independently hydrogen, halogen, C₁ -C₆alkyl, C₂ -C₆ alkenyl, C₂ -C₆ alkynyl, nitro, cyano, hydroxy, thiocyano,--N(R¹¹)(R¹²), C₁ -C₆ haloalkyl, C₁ -C₆ alkoxy, C₂ -C₆ haloalkoxy, (C₁-C₆)alkoxy-(C₁ -C₆)alkyl, halo(C₁ -C₆) alkoxy-(C₁ -C₆)alkyl, --C(X)--R¹⁰or --S(O)_(k) --R¹⁰ ;

X is oxygen or sulfur;

R is hydrogen, hydrocarbyl, hydrocarbyl substituted with one or more ofhalogen or C₁ -C₆ alkoxy or is of the formula --C(Q)--R⁶,--C(O)--C(O)--R⁶, --S(O)₂ --R⁶, --P(Y)(R¹¹)(R¹²) or --Si(R¹³)(R¹⁴)(R¹⁵);

wherein:

Q is oxygen or sulfur;

R⁶ is hydrocarbyl, substituted hydrocarbyl, hydrocarbyloxy, substitutedhydrocarbyloxy, hydrocarbyl-S--, substituted hydrocarbyl-S-- or is ofthe formula --N(R⁷)(R⁸);

wherein R⁷ and R⁸ are each independently hydrogen, hydrocarbyl,substituted hydrocarbyl, hydrocarbyloxy, substituted hydrocarbyloxy,pyridyl, furyl, thienyl, (C₁ -C₆)alkoxycarbonyl(C₁ -C₆) alkyl,hydroxycarbonyl(C₁ -C₆)alkyl, or N(R⁹)--(R¹⁰) wherein R⁹ and R¹⁰ areeach independently hydrogen, C₁ -C₆ alkyl or phenyl;

or R⁷ and R⁸ together with the nitrogen to which they are bound form anaziridine, piperazine, morpholine, thiomorpholine, thiomorpholine1-oxide, thiomorpholine 1,1-dioxide, hexamethyleneimine, piperidine orpyrrolidine ring, any of which may be optionally substituted with C₁ -C₆alkyl;

R¹¹ and R¹² are each independently C₁ -C₆ alkyl, C₁ -C₆ alkylthio or C₁-C₆ alkoxy;

R¹³, R¹⁴ and R¹⁵ are each independently C₁ -C₆ alkyl, C₁ -C₆ alkoxy, C₁-C₆ haloalkyl, aryl or arylalkyl;

k is 0, 1 or 2;

n is 0 or 1;

and agriculturally acceptable salts thereof.

In another aspect, this invention is directed to a herbicidalcomposition comprising:

(A) a compound of the formula (I): ##STR7## wherein:

Ar is a substituted or unsubstituted 5- or 6-membered heteroaryl grouphaving 1, 2 or 3 ring nitrogen atoms with the remainder of the ringatoms being carbon; a substituted or unsubstituted 5-membered heteroarylgroup having a ring heteroatom of oxygen or sulfur with the remainder ofthe ring atoms being carbon; or a substituted or unsubstituted5-membered heteroaryl group having one ring nitrogen atom and either anoxygen or sulfur ring heteroatom with the remainder of the ring atomsbeing carbon;

R¹, R², R³ and R⁴ are each independently hydrogen, halogen, C₁ -C₆alkyl, C₂ -C₆ alkenyl, C₂ -C₆ alkynyl, nitro, cyano, hydroxy, thiocyano,--N(R¹¹)(R¹²), C₁ -C₆ haloalkyl, C₁ -C₆ alkoxy, C₁ -C₆ haloalkoxy, (C₁-C₆)alkoxy-(C₁ -C₆)alkyl, halo(C₁ -C₆)alkoxy-(C₁ -C₆)alkyl, --C(X)--R¹⁰or --S(O)_(k) --R¹⁰ ;

X is oxygen or sulfur;

R is hydrogen, hydrocarbyl, hydrocarbyl substituted with one or more ofhalogen or C₁ -C₆ alkoxy or is of the formula --C(Q)--R⁶,--C(O)--C(O)--R⁶, --S(O)₂ --R⁶, --P(Q)(R¹¹)(R¹²) or --Si(R¹³)(R¹⁴)(R¹⁵);

wherein:

Q is oxygen or sulfur;

R⁶ is hydrocarbyl, substituted hydrocarbyl, hydrocarbyloxy, substitutedhydrocarbyloxy, hydrocarbyl-S--, substituted hydrocarbyl-S-- or is ofthe formula --N(R⁷)(R⁸);

wherein R⁷ and R⁸ are each independently hydrogen, hydrocarbyl,substituted hydrocarbyl, hydrocarbyloxy, substituted hydrocarbyloxy,pyridyl, furyl, thienyl, (C₁ -C₆)alkoxycarbonyl(C₁ -C₆)alkyl,hydroxycarbonyl(C₁ -C₆)alkyl, or N(R⁹)--(R¹⁰) wherein R⁹ and R¹⁰ areeach independently hydrogen, C₁ -C₆ alkyl or phenyl;

or R⁷ and R⁸ together with the nitrogen to which they are bound form anaziridine, piperazine, morpholine, thiomorpholine, thiomorpholine1-oxide, thiomorpholine 1,1-dioxide, hexamethyleneimine, piperidine orpyrrolidine ring, any of which may be optionally substituted with C ₁-C₆ alkyl;

R¹¹ and R¹² are each independently C₁ -C₆ alkyl, C₁ -C₆ alkylthio or C₁-C₆ alkoxy;

R¹³, R¹⁴ and R¹⁵ are each independently C₁ -C₆ alkyl, C₁ -C₆ alkoxy, C₁-C₆ haloalkyl, aryl or arylalkyl;

k is 0, 1 or 2; and

n is 0 or 1

or an agriculturally acceptable salt thereof; and

(B) a carrier therefor.

In yet another aspect, this invention is directed to a method forcontrolling undesirable vegetation comprising applying to the area wherecontrol is desired an herbicidally effective amount of a compound of theformula (I): ##STR8## wherein:

Ar is a substituted or unsubstituted 5- or 6-membered heteroaryl grouphaving 1, 2 or 3 ring nitrogen atoms with the remainder of the ringatoms being carbon; a substituted or unsubstituted 5-membered heteroarylgroup having a ring heteroatom of oxygen or sulfur with the remainder ofthe ring atoms being carbon; or a substituted or unsubstituted5-membered heteroaryl group having one ring nitrogen atom and either anoxygen or sulfur ring heteroatom with the remainder of the ring atomsbeing carbon;

R¹, R², R³ and R⁴ are each independently hydrogen, halogen, C₁ -C₆alkyl, C₂ -C₆ alkenyl, C₂ -C₆ alkynyl, nitro, cyano, hydroxy, thiocyano,--N(R¹¹)(R¹²), C₁ -C₆ haloalkyl, C₁ -C₆ alkoxy, C₁ -C₆ haloalkoxy, (C₁-C₆)alkoxy-(C₁ -C₆)alkyl, halo(C₁ -C₆)alkoxy-(C₁ -C₆)alkyl, --C(X)--R¹⁰or --S(O)_(k) --R¹⁰ ;

X is oxygen or sulfur;

R is hydrogen, hydrocarbyl, hydrocarbyl substituted with one or more ofhalogen or C₁ -C₆ alkoxy or is of the formula --C(Q)--R⁶,--C(O)--C(O)--R⁶, --S(O)₂, --P(Q)(R¹¹)(R¹²) or --Si(R¹³) (R¹⁴) (R¹⁵);

wherein:

Q is oxygen or sulfur;

R₆ is hydrocarbyl, substituted hydrocarbyl, hydrocarbyloxy, substitutedhydrocarbyloxy, hydrocarbyl-S--, substituted hydrocarbyl-S-- or is ofthe formula --N(R⁷)(R⁸);

wherein R⁷ and R⁸ are each independently hydrogen, hydrocarbyl,substituted hydrocarbyl, hydrocarbyloxy, substituted hydrocarbyloxy,pyridyl, furyl, thienyl, (C₁ -C₆ )alkoxycarbonyl(C₁ -C₆)alkyl,hydroxycarbonyl(C₁ -C₆)alkyl, or N(R⁹)(R¹⁰) wherein R⁹ and R¹⁰ are eachindependently hydrogen, C₁ -C₆ alkyl or phenyl;

or R⁷ and R⁸ together with the nitrogen to which they are bound form anaziridine, piperazine, morpholine, thiomorpholine, thiomorpholine1-oxide, thiomorpholine 1,1-dioxide, hexamethyleneimine, piperidine orpyrrolidine ring, any of which may be optionally substituted with C₁ -C₆alkyl;

R¹¹ and R¹² are each independently C₁ -C₆ alkyl, C₁ -C₆ alkylthio or C₁-C₆ alkoxy;

R¹³, R¹⁴ and R¹⁵ are each independently C₁ -C₆ alkyl, C₁ -C₆ alkoxy, C₁-C₆ haloalkyl, aryl or arylalkyl;

k is 0, 1 or 2; and

n is 0 or 1;

or an agriculturally acceptable salt thereof.

In yet a further aspect, because the compounds of this invention whereinXR is OH are useful intermediates for producing the other compounds ofthis invention, as well as possessing herbicidal activity, thisinvention is directed to compounds of the formula (II): ##STR9##wherein:

Ar is a substituted or unsubstituted 5- or 6-membered heteroaryl grouphaving 1, 2 or 3 ring nitrogen atoms with the remainder of the ringatoms being carbon; a substituted or unsubstituted 5-membered heteroarylgroup having a ring heteroatom of oxygen or sulfur with the remainder ofthe ring atoms being carbon; or a substituted or unsubstituted5-membered heteroaryl group having one ring nitrogen atom and either anoxygen or sulfur ring heteroatom with the remainder of the ring atomsbeing carbon;

R¹, R², R³ and R⁴ are each independently hydrogen, halogen, C₁ -C₆alkyl, C₂ -C₆ alkenyl, C₂ -C₆ alkynyl, nitro, cyano, hydroxy, thiocyano,--N(R¹¹)(R¹²), C₁ -C₆ haloalkyl, C₁ -C₆ alkoxy, C₁ -C₆ haloalkoxy, (C₁-C₆)alkoxy-(C₁ -C₆)alkyl, halo(C₁ -C₆)alkoxy-(C₁ -C₆)alkyl, --C(X)--R¹⁰or --S(O)_(k) --R¹⁰ ;

R¹⁰ is hydrogen, C₁ -C₆ alkyl or phenyl;

R¹¹ and R¹² are each independently C₁ -C₆ alkyl, C₁ -C₆ alkylthio or C₁-C₆ alkoxy;

k is 0, 1 or 2;

n is 0 or 1;

and agriculturally acceptable salts thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The novel herbicidal compounds of this invention are of the formula (I):##STR10## wherein:

Ar is a substituted or unsubstituted 5- or 6-membered heteroaryl grouphaving 1, 2 or 3 ring nitrogen atoms with the remainder of the ringatoms being carbon; a substituted or unsubstituted 5-membered heteroarylgroup having a ring heteroatom of oxygen or sulfur with the remainder ofthe ring atoms being carbon; or a substituted or unsubstituted5-membered heteroaryl group having one ring nitrogen atom and either anoxygen or sulfur ring heteroatom with the remainder of the ring atomsbeing carbon.

R¹, R², R³ and R⁴ are each independently hydrogen, halogen, C₁ -C₆alkyl, C₂ -C₆ alkenyl, C₁ -C₆ alkynyl, nitro, cyano, hydroxy, thiocyano,--N(R¹¹)(R¹²), C₁ -C₆ haloalkyl, C₁ -C₆ alkoxy, C₁ -C₆ haloalkoxy, (C₁-C₆)alkoxy-(C₁ -C₆)alkyl, halo(C₁ -C₆)alkoxy-(C₁ -C₆)alkyl, --C(X)--R¹⁰or --S(O)_(k) --R¹⁰ ;

X is oxygen or sulfur;

R is; hydrogen, hydrocarbyl, hydrocarbyl substituted with one or more ofhalogen or C₁ -C₆ alkoxy or is of the formula --C(Q)--R⁶,--C(O)--C(O)--R⁶, --S(O)₂ --R⁶, --P(Q)(R¹¹)(R¹²) or --Si(R¹³)(R¹⁴)(R¹⁵);

wherein:

Q is oxygen or sulfur;

R⁶ is hydrocarbyl, substituted hydrocarbyl, hydrocarbyloxy, substitutedhydrocarbyloxy, hydrocarbyl-S--, substituted hydrocarbyl-S-- or is ofthe formula --N(R⁷)(R⁸);

wherein R⁷ and R⁸ are each independently hydrogen, hydrocarbyl,substituted hydrocarbyl, hydrocarbyloxy, substituted hydrocarbyloxy,pyridyl, furyl, thienyl, (C₁ -C₆)alkoxycarbonyl(C₁ -C₆)alkyl,hydroxycarbonyl(C₁ -C₆)alkyl, or N(R⁹)--(R¹⁰) wherein R⁹ and R¹⁰ areeach independently hydrogen, C₁ -C₆ alkyl or phenyl;

or R⁷ and R⁸ together with the nitrogen to which they are bound form anaziridine, piperazine, morpholine, thiomorpholine, thiomorpholine1-oxide, thiomorpholine 1,1-dioxide, hexamethyleneimine, piperidine orpyrrolidine ring, any of which may be optionally substituted with C₁ -C₆alkyl;

R¹¹ and R¹² are each independently C₁ -C₆ alkyl, C₁ -C₆ alkylthio or C₁-C₆ alkoxy;

R¹³, R¹⁴ and R¹⁵ are each independently C₁ -C₆ alkyl, C₁ -C₆ alkoxy, C₁-C₆ haloalkyl, aryl or arylalkyl;

k is 0, 1 or 2; and

n is 0 or 1;

and agriculturally acceptable salts thereof.

Preferably,

Ar is a substituted or unsubstituted pyridyl, pyrimidinyl, pyrrolyl,furyl, thienyl, pyrazinyl, thiazolyl, oxazolyl or triazinyl group;

R¹, R², R³ and R⁴ are each independently hydrogen, halogen, C₁ -C₆alkyl, C₁ -C₆ haloalkyl, C₁ -C₆ alkoxy, C₁ -C₆ haloalkoxy, nitro or--S(O)_(k) --(C₁ -C₃)alkyl wherein k is 0, 1 or 2, with at least one ofR¹, R², R³ and R⁴ not being hydrogen;

X is oxygen; and

R is of the formula ##STR11## wherein R⁶ is C₁ -C₁₂ alkyl, C₁ -C₆haloalkyl, phenyl or is N(R⁷)(R⁸), wherein R⁷ and R⁸ are eachindependently C₁ -C₁₂ alkyl, hydrogen, C₂ -C₁₂ alkenyl, C₂ -C₁₂ alkynyl,C₁ -C₁₂ haloalkyl, C₁ -C₆ alkoxy, (C₁ -C₆)alkoxy(C₁ -C₆)alkyl or R⁷ andR⁸ together with the nitrogen to which they are bound form a morpholine,piperidine or pyrrolidine ring.

More preferably,

Ar is a substituted or unsubstituted pyridyl, pyrimidinyl, pyrrolyl,furyl, thienyl, pyrazinyl, thiazolyl, oxazolyl or triazinyl group;

R¹ is trifluoromethyl, fluoro, chloro, bromo, iodo, methoxy, methyl orethyl;

R², R³ and R⁴ are each independently hydrogen, chloro or bromo;

X is oxygen; and

R is of the formula ##STR12## wherein R⁶ is C₁ -C₆ alkyl or is of theformula N(R⁷)(R⁸), wherein R⁷ and R⁸ are independently hydrogen, C₁ -C₆haloalkyl, C₁ -C₆ alkyl or C₂ -C₆ alkenyl.

The term "substituted . . . heteroaryl group" as used in the definitionof Ar is intended to include heteroaryl groups, as defined above, havingone or more substituents independently selected from the groupconsisting of halogen, C₁ -C₆ alkyl, C₂ -C₆ alkenyl, C₂ -C₆ alkynyl, C₁-C₆ alkoxy, C₁ -C₆ alkylcarbamylthio, mercapto, C₁ -C₆ haloalkyl, C₁ -C₆haloalkoxy nitro, cyano, hydroxy, thiocyano, (C₁ -C₆) alkoxy-(C₁ -C₆)alkyl, --S(O)_(k) --R¹⁰ or --N(R¹¹)(R¹²), wherein k, R¹⁰, R¹¹ and R¹²have the meanings set forth above; and to include N-oxides of theheteroaryl group. Of these substituents, halogen, C₁ -C₆ alkyl, C₁ -C₆alkoxy and C₁ -C₆ haloalkyl are especially preferred.

One group of preferred 3-substituted pyridine compounds is of theformula: ##STR13## wherein X, R, R¹, R², R³, R⁴ and n have the samemeanings as in formula (I);

m is 0, 1, 2, 3 or 4; and when m is not 0, each Y is independentlyhalogen, C₁ -C₆ alkyl, C₁ -C₆ haloalkyl, C₁ -C₆ alkoxy, C₂ -C₆ alkenyl,C₂ -C₆ alkynyl, C₁ -C₆ alkylcarbamylthio, mercapo, C₁ -C₆ haloalkoxy,nitro, cyano, hydroxy, thiocyano, (C₁ -C₆)-alkoxy-(C₁-C₆)alkyl,--S(O)_(k) --R¹⁰ or --N(R¹¹)(R¹²), wherein k, R¹⁰, R¹¹ and R¹²have the meanings set forth above.

Another group of preferred compounds is 3-substituted pyridines of theformula: ##STR14## wherein X, R, R¹, R², R³, R⁴ and n have the samemeanings as set forth above;

p is 0, 1, 2 or 3; and

when p is not 0, each Y has the same meaning as set forth with respectto formula (III).

Yet another group of preferred compounds is 3-substituted pyridines ofthe formula: ##STR15## wherein z is nitrogen, oxygen or sulfur; and

X, R, R¹, R², R³, R⁴, n, Y and m have the same meanings as set forthabove with respect to formula (III).

A still further group of preferred compounds is 3-substituted pyridinesof the formula ##STR16## wherein Z is nitrogen, oxygen or sulfur; and X,R, R¹, R²,R³, R⁴, n, Y and p have the same meanings as set forth abovewith respect to formula IV.

The formulae given above are intended to include tautomeric forms of thestructures drawn therein, as well as physically distinguishablemodifications of the compounds which may arise, for example, fromdifferent ways in which the molecules are arranged in a crystal lattice,or from the inability of parts of the molecule to rotate freely inrelation to other parts, or from geometrical isomerism, or fromintramolecular or intermolecular hydrogen bonding, or otherwise.

The compounds of such formulae can exist in enantiomeric forms. Theinvention includes both individual enantiomers and mixtures of the twoin all proportions.

As is employed herein, the term "hydrocarbyl", whether representing asubstituent on its own or whether it is part of the definition of alarger group (e.g., as in hydrocarbyloxy, hydrocarbyl-S(O)_(k) --, etc.)is intended to include hydrocarbyl groups having from 1 to 12 carbonatoms. The term hydrocarbyl therefore includes, for example, C₁ to C₁₂alkyl including both straight and branched chain isomers (e.g., methyl,ethyl, propyl, and hexyl); cycloalkyl of 3 to 12 carbon atoms (e.g.,cyclopropyl, cyclobutyl and cyclohexyl); C₂ to C₁₂ alkenyl including forexample allyl and crotyl; C₂ to C₁₂ alkynyl (e.g., propynyl); phenyl;phenylalkyl; alkylphenyl, alkenylphenyl, alkynylphenyl, alkylbenzyl,alkenylbenzyl, alkynyl benzyl, naphthyl and the like.

The term "substituted hydrocarbyl" is intended to include hydrocarbylgroups, as defined above, having one or more substituents selected fromthe group consisting of halogen (i.e., fluorine, chlorine, bromine, andiodine); C₁₋₄ alkoxy; C₁₋₄ alkyl-S(O)_(k) --; nitro; cyano; carboxy, andsalts, amides and esters thereof; alkanoyl of 2 to 4 carbon atoms; andphenyl optionally substituted by one or more C₁₋₄ alkyl, C₁₋₄ alkoxy,C₁₋₄ alkyl-S(O)_(k) --, nitro, fluorine, chlorine, bromine, cyano, orCF₃ groups. In the above definitions, k is 0, 1 or 2.

Further, when the hydrocarbyl radical is a substituted aryl radical(e.g., phenyl, benzyl or naphthyl), the substituents may include one ormore of the substituents listed in the last foregoing paragraph.

The expression "salts, amides, and esters thereof" used above inrelation to carboxy substitution includes, for example, salts formedfrom alkali metal (e.g., sodium, potassium, and lithium), alkaline earthmetals (e.g., calcium and magnesium), the ammonium ion, and substitutedammonium ions wherein one, two, three, or four of the hydrogen atomshave been replaced by optionally substituted C₁ -C₆ hydrocarbyl moietiesas defined above.

Further, in the above definitions the term "halogen" includes fluoro,chloro, bromo and iodo groups. In polyhalogenated groups the halogensmay be the same or different.

Particularly preferred compounds include:

1,1-bis-(4-trifluoromethylpyrid-3-yl)-1-trimethylacetoxymethane;

1,1-bis-(4-trifluoromethylpyrid-3-yl)-1-N,N-dimethylcarbamyloxymethane;

1,1-bis-(4-trifluoromethylpyrid-3-yl)-1-N-ethylcarbamyloxymethane;

1,1-bis-(4-trifluoromethylpyrid-3-yl)-1-N-methylcarbamyloxymethane;

1-(4-trifluoromethylpyrid-3-yl)-1-(4-methoxypyrimidin-5-yl)-1-N,N-dimethylcarbamyloxymethane; and

1-(4-trifluoromethylpyrid-3-yl)-1-(4-methoxypyrimidin-5-yl)-1-N-ethylcarbamyloxymethane.

The compounds of the present invention have been found to be activeherbicides, possessing utility as preemergence and post-emergenceherbicides and useful against a wide range of plant species includingbroadleaf, grassy and perennial species.

This invention therefore also relates to a method for controllingundesirable vegetation comprising applying to a locus where control ofsuch vegetation is desired, either prior or subsequent to the emergenceof such vegetation, a herbicidally effective amount of a compound asdescribed herein, together with an inert diluent or carrier suitable foruse with herbicides.

The terms "herbicide" and "herbicidal" are used herein to denote theinhibitive control or modification of undesired plant growth. Inhibitivecontrol and modification include all deviations from natural developmentsuch as, for example, total killing, growth retardation, defoliation,desiccation, regulation, stunting, tillering, stimulation, leaf burn anddwarfing. The term "herbicidally effective amount" is used to denote anyamount which achieves such control or modification when applied to theundesired plants themselves or to the area in which these plants aregrowing. The term "plants" is intended to include germinated seeds,emerging seedlings and established vegetation, including both roots andabove-ground portions.

The term "agriculturally acceptable salt" is easily determined by one ofordinary skill in the art and includes hydrohalogen, acetic, sulfonic,phosphonic, inorganic and organic acid salts.

In general, the compounds of this invention are prepared by (A) reactinga substituted pyridine compound with a substituted or unsubstitutedheteroaryl carboxaldehyde in the presence of a suitable base to form a3-substituted pyridine compound of formula (II) above; and, whereappropriate, (B) reacting such 3-substituted pyridine compound with anappropriate derivatizing agent (e.g., an alkyl or aryl acid halide,carbamoyl halide, alkyl halide, sulfonyl halide or phosphoryl halide ortrialkylsilylhalide) or an appropriate isocyanate, or sequentially firstwith phosgene or a phosgene equivalent and then with an appropriateamine, to produce the desired compound.

Typically, about 1-2 equivalents of an appropriate base (such as lithiumdiisopropyl amide or n-butyl lithium) and a substituted pyridinecompound, as defined above, in a solvent (such as ethylene glycoldimethyl ether, tetrahydrofuran, diethyl ether or the like) are combinedat a temperature of between about -100° and about 0° C. After suitableblending, about 1-2 equivalents of the heteroaryl carboxaldehyde aregenerally added.

This reaction mixture is typically agitated and slowly warmed up toambient temperature (about 25° C.) over a period of 1-24 hours. Thereaction may be quenched with an aqueous solution and the 3-substitutedpyridine compound so produced may be recovered by conventionaltechniques (such as extraction, filtration and the like) and purified byknown methods, e.g., flash chromatography.

In the second step, the 3-substituted pyridine compound of formula (II),in a suitable solvent (such as tetrahydrofuran, methylene chloride, orthe like) may typically be added to between about 1 and about 4equivalents of an appropriate base (such as sodium hydride ortriethylamine) at about 0° C. Between about 1 and about 3 equivalents ofderivatizing agent (such as a carbamoyl halide, an alkyl halide, asulfonyl halide or a phosphosphoryl halide, an alkyl or aryl acid halideor trialkylsilyl halide) is then added and the mixture agitated untilthe reaction is complete. The reaction may be quenched by the additionof an aqueous solution, and the products recovered by conventionaltechniques, such as extraction, filtration and the like. The product sorecovered may then be purified by conventional techniques such as flashchromatography or the like.

Alternatively, in the second step, the 3-substituted pyridine compoundin suitable solvent (such as tetrahydrofuran, methylene chloride or thelike) may be added to between about 2 and about 3 equivalents of anappropriate isocyanate. Between about 1 and about 10 mole percent of oneor more appropriate catalysts, e.g., triethyl amine or dibutyl tindilaurate, may be added and the reaction mixture agitated at betweenabout 0° and 100° C. for an appropriate period (e.g., 2 to 24 hours).The product may be recovered by conventional techniques (such asextraction, filtration or the like) and may be purified by conventionaltechniques such as flash chromatography or the like.

The substituted pyridine starting materials are either commerciallyavailable or may be prepared by one of ordinary skill in the artemploying methods such as those described in "Heterocyclic Compounds,Pyridine and Its Derivatives", R. A. Abramovitch, Vol. 14, Wiley, 1973.The substituted heterocyclic starting materials are commerciallyavailable or may be prepared employing techniques such as thosedescribed in T. Kelley, W. Xu and J. Sundareson, Tetrahedron Letters,34, 6173 (1993) or as described below.

The herbicidal compositions of this invention comprise a compound offormula (I) above and a suitable carrier, which carriers are well knownto one of ordinary skill in the art.

The compounds of the present invention are useful as herbicides and canbe applied in a variety of ways known to those skilled in the art, atvarious concentrations. The compounds are useful in controlling thegrowth of undesirable vegetation by pre-emergence or post-emergenceapplication to the locus where control is desired. In practice, thecompounds are applied as formulations containing the various adjuvantsand carriers known to or used in the industry for facilitatingdispersion. The choice of formulation and mode of application for anygiven compound may affect its activity, and selection will be madeaccordingly. The compounds of the invention may thus be formulated asgranules, as wettable powders, as emulsifiable concentrates, as powdersor dusts, as flowables, as solutIons, suspensions or emulsions, or incontrolled-release forms such as microcapsules. These formulations maycontain as little as about 0.5% to as much as amount 95% or more byweight of active ingredient. The optimum amount for any given compoundwill depend upon the nature of the seeds or plants to be controlled. Therate of application will generally vary from about 0.01 to about 10pounds per acre, preferably from about 0.02 to about 4 pounds per acre.

Wettable powders are in the form of finely divided particles whichdisperse readily in water or other liquid carriers. The particlescontain the active ingredient retained in a solid matrix. Typical solidmatrices include fuller's earth, kaolin clays, silicas and other readilywet organic or inorganic solids. Wettable powders normally contain about5% to about 95% of the active ingredient plus a small amount of wetting,dispersing, or emulsifying agent.

Emulsifiable concentrates are homogeneous liquid compositionsdispersible in water or other liquid, and may consist entirely of theactive compound with a liquid or solid emulsifying agent, or may alsocontain a liquid carrier, such as xylene, heavy aromatic naphthas,isophorone and other non-volatile organic solvents. In use, theseconcentrates are dispersed in water or other liquid and normally appliedas a spray to the area to be treated. The amount of active ingredientmay range from about 0.5% to about 95% of the concentrate.

Granular formulations include both extrudates and relatively coarseparticles, and are usually applied without dilution to the area in whichsuppression of vegetation is desired. Typical carriers for granularformulations include sand, fuller's earth, attapulgite clay, bentoniteclays, montmorillonite clay, vermiculite, perlite and other organic orinorganic materials which absorb or which can be coated with the activecompound. Granular formulations normally contain about 5% to about 25%active ingredients which may include surface-active agents such as heavyaromatic naphthas, kerosene and other petroleum fractions, or vegetableoils; and/or stickers such as dextrins, glue or synthetic resins.

Dusts are free-flowing admixtures of the active ingredient with finelydivided solids such as talc, clays, flours and other organic andinorganic solids which act as dispersants and carriers.

Microcapsules are typically droplets or granules of the active materialenclosed in an inert porous shell which allows escape of the enclosedmaterial to the surroundings at controlled rates. Encapsulated dropletsare typically about 1 to 50 microns in diameter. The enclosed liquidtypically constitutes about 50 to 95% of the weight of the capsule, andmay include solvent in addition to the active compound. Encapsulatedgranules are generally porous granules with porous membranes sealing thegranule pore openings, retaining the active species inside the granulepores. Granules typically range from 1 millimeter to 1 centimeter,preferably 1 to 2 millimeters in diameter. Granules are formed byextrusion, agglomeration or prilling, or are naturally occurring.Examples of such materials are vermiculite, sintered clay, kaolin,attapulgite clay, sawdust and granular carbon. Shell or membranematerials include natural and synthetic rubbers, cellulosic materials,styrene-butadiene copolymers, polyacrylonitriles, polyacrylates,polyesters, polyamides, polyureas, polyurethanes and starch xanthates.

Other useful formulations for herbicidal applications include simplesolutions of the active ingredient in a solvent in which it iscompletely soluble at the desired concentration, such as acetone,alkylated naphthalenes, xylene and other organic solvents. Pressurizedsprayers, wherein the active ingredient is dispersed in finely-dividedform as a result of vaporization of a low boiling dispersant solventcarrier, such as the Freons, may also be used.

Many of these formulations include wetting, dispersing or emulsifyingagents. Examples are alkyl and alkylaryl sulfonates and sulfates andtheir salts; polyhydric alcohols; polyethoxylated alcohols; esters andfatty amines. These agents when used normally comprise from 0.1% to 15%by weight of the formulation.

Each of the above formulations can be prepared as a package containingthe herbicide together with other ingredients of the formulation(diluents, emulsifiers, surfactants etc.). The formulations can also beprepared by a tank mix method, in which the ingredients are obtainedseparately and combined at the grower site.

The compounds of the present invention are also useful when combinedwith other herbicides and/or defoliants, desiccants, growth inhibitors,and the like. These other materials can comprise from about 5% to about95% of the active ingredients in the formulations. These combinationsfrequently provided a higher level of effectiveness in controlling weedsand often provide results unattainable with separate formulations of theindividual herbicides.

Examples of other herbicides, defoliants, desiccants and plant growthinhibitors with which the compounds of this invention can be combinedare:

A. benzo-2,1,3-thiadlazin-4-one-2,2-dioxides such as bentazone;

B. hormone herbicides, particularly the phenoxy alkanoic acids such asMCPA, MCPA-thioethyl, dichlorprop, 2,4,5-T, MCPB, 2,4-D, 2,4-DB,mecoprop, trichlopyr, fluroxypyr, clopyralid, and their derivatives(e.g. salts, esters and amides);

C. 4-benzoylpyrazole derivatives such as pyrazoxyfen, pyrazolate andbenzofenap;

D. dinitrophenols and their derivatives (e.g. acetates such as DNOC,dinoterb, dinoseb and its ester, dinoseb acetate;

E. dinitroaniline herbicides such as dinitramine, trifluralin,ethalfluralin, pendimethalin; and oryzalin;

F. arylurea herbicides such as diuron, flumeturon, metoxuron, neburon,isoproturon, chlorotoluron, chloroxuron, linuron, monolinuron,chlorobromuron, daimuron, and methabenzthiazuron;

G. phenylcarbamoyloxyphenylcarbamates such as phenmedipham anddesmedipham;

H. 2-phenylpyridazin-3-ones such as chloridazon, and norflurazon;

I. uracil herbicides such as lenacil, bromacil and terbacil;

J. triazine herbicides such as atrazine, simazine, aziprotryne,cyanazine, prometryn, dimethametryn, simetryne, and terbutryn;

K. phosphorothicate herbicides such as piperophos, bensulide, andbutamifos;

L. thiolcarbamate herbicides such as cycloate, vernolate, molinate,thiobencarb, butylate*, EPTC*, triallate, diallate, ethyl esprocarb,tiocarbazil, pyridate, and dimepiperate;

M. 1,2,4-triazin-5-one herbicides such as metamitron and metribuzin;

N. benzoic acid herbicides such as 2,3,6-TBA, dicamba and chloramben;

O. anilide herbicides such as pretilachlor, butachlor, the correspondingalachlor, the corresponding compound propachlor, propanil, metazachlor,metolachlor, acetochlor, and dimethachlor;

P. dihalobenzonitrile herbicides such as dichlobenil, bromoxynil andioxynil;

Q. haloalkanoic herbicides such as dalapon, TCA and salts thereof;

R. diphenylether herbicides such as lactofen, fluroglycofen or salts oresters thereof, nitrofen, bifenox, acifluorfen and salts and estersthereof, oxyfluorfen and fomesafen; chlornitrofen and chlomethoxyfen;

S. phenoxyphenoxypropionate herbicides such as diclofop and estersthereof such as the methyl ester, fluazifop and esters thereof,haloxyfop and esters thereof, quizalofop and esters thereof andfenoxaprop and esters thereof such as the ethyl ester;

T. triketone and cyclohexanedione herbicides such as alloxydim,sulcotrione and salts thereof, sethoxydim, cycloxydim, tralkoxydim, andclethodim;

U. sulfonyl urea herbicides such as chlorosulfuron, sulfometuron,metsulfuron and esters thereof; benzsulfuron and esters thereof such asthe ester thereof methyl, DPX-M6313, chlorimuron and esters such as theethyl ester thereof, pirimisulfuron and esters such as the methyl esterthereof, DPX-LS300 and pyrazosulfuron;

V. imidazolidinone herbicides such as imazaquin, imazamethabenz,imazapyr and isopropylammonium salts thereof, imazethapyr;

W. arylanilide herbicides such as flamprop and esters thereof,benzoylprop-ethyl and diflufenican;

X. amino acid herbicides such as glyphosate and glufosinate and theirsalts and esters, sulphosate, and bilanafos;

Y. organoarsenical herbicides such as MSMA;

Z. herbicidal anide derivative such as napropamide, propyzamide,carbetamide, tebutam, bromobutide, isoxaben, naproanilide, diphenamid,and naptalam;

AA. miscellaneous herbicides including ethofumesate, cinmethylin,difenzoquat and salts thereof such as the methyl sulfate salt,clomazone, oxadiazon, bromofenoxim, barban, tridiphane, (in the ratio3:1) flurochloridone, quinchlorac and mefanacet;

BB. examples of useful contact herbicides include bipyridyliumherbicides such as those in which the active entity is parquet and thosein which the active entity is diquat.

These formulations can be applied to the areas where control is desiredby conventional methods. Dust and liquid compositions, for example, canbe applied by the use of power-dusters, boom and hand sprayers and spraydusters. The formulations can also be applied from airplanes as a dustor a spray or by rope wick applications. To modify or control growth ofgerminating seeds or emerging seedlings, dust and liquid formulationscan be distributed in the soil to a depth of at least one-half inchbelow the soil surface or applied to the soil surface only, by sprayingor sprinkling. The formulations can also be applied by addition toirrigation water. This permits penetration of the formulations into thesoil together with the irrigation water. Dust compositions, granularcompositions or liquid formulations applied to the surface of the soilcan be distributed below the surface of the soil by conventional meanssuch as discing, dragging or mixing operations.

The following are examples of typical formulations.

    ______________________________________                                        5% dust:  5        parts active compound                                                95       parts talc                                                 2% dust:  2        parts active compound                                                1        part highly dispersed silicic acid                                   97       parts talc                                                 ______________________________________                                    

These dusts are formed by mixing the components then grinding themixture to the desired particle size.

    ______________________________________                                        5% granules:                                                                            5        parts active compound                                                0.25     part epichlorohydrin                                                 0.25     part cetyl polyglycol ether                                          3.5      parts polyethylene glycol                                            91       part kaolin (particle size 0.3-0.8 mm)                     ______________________________________                                    

Granules are formed by mixing the active compound with epichlorohydrinand dissolving the mixture in 6 parts of acetone. The polyethyleneglycol and cetyl polyglycol ether are then added. The resultant solutionis sprayed on the kaolin and the acetone evaporated in vacuo.

    ______________________________________                                        Wettable powders:                                                             ______________________________________                                        70%:    70       parts active compound                                                5        parts sodium dibutylnaphthylsulfonate                                3        parts naphthalenesulfonic                                                     acid/phenolsulfonic                                                           acid/formaldehyde condensate (3:2:1)                                 10       parts kaolin                                                         12       parts Champagne chalk                                        40%:    40       parts active compound                                                5        parts sodium lignin sulfonate                                        1        part sodium dibutylnaphthalene sulfonic                                       acid                                                                 54       parts silicic acid                                           25%:    25       parts active compound                                                4.5      parts calcium lignin sulfate                                         1.9      parts Champagne chalk/hydroxyethyl                                            cellulose (1:1)                                                      1.5      parts sodium dibutylnaphthalene                                               sulfonate                                                            19.5     silicic acid                                                         19.5     parts Champagne chalk                                                28.1     parts kaolin                                                 25%:    25       parts active compound                                                2.5      parts isooctylphenoxy-polyethylene-                                           ethanol                                                              1.7      parts Champagne chalk/hydroxyethyl                                            cellulose (1:1)                                                      8.3      parts sodium aluminum silicate                                       16.5     parts kieselguhr                                                     46       parts kaolin                                                 10%:    10       parts active compound                                                3        parts of a mixture of sodium salts of                                         saturated fatty alcohol sulfates                                     5        parts naphthalenesulfonic acid/                                               formaldehyde condensate                                              82       parts kaolin                                                 ______________________________________                                    

These wettable powders are prepared by intimately mixing the activecompounds with the additives in suitable mixers, and grinding theresulting mixture in mills or rollers.

    ______________________________________                                        Emulsifiable concentrate:                                                     ______________________________________                                        25%:    25         parts active substance                                             2.5        parts epoxidized vegetable oil                                     10         parts of an alkylarylsulfonate/fatty                                          alcohol polyglycol ether mixture                                   5          parts dimethylformamide                                            57.5       parts xylene                                               ______________________________________                                    

The amount of the present compositions which constitute a herbicidallyeffective amount depends upon the nature of the seeds or plants to becontrolled. The rate of application of active ingredients varies fromabout 0.01 to about 25 pounds per acre, preferably about 0.10 to about10 pounds per acre with the actual amount depending on the overall costsand the desired results. It will be readily apparent to one skilled inthe art that compositions exhibiting lower herbicidal activity willrequire a higher dosage than more active compounds for the same degreeof control.

EXAMPLES

The following examples are intended to further illustrate the presentinvention and are not intended to limit the scope of this invention inany manner whatsoever.

Example 1

Preparation of 1-(4-bromopyrid-3-yl)-1-(4-chloropyrid-3-yl)methanol(Compound No. 5)

Five grams (g) of 4-chloropyridine hydrochloride were placed into a 30milliliters (ml) of diethyl ether in a 200 ml beaker equipped with amagnetic stirrer. 1.8 grams of sodium hydroxide in 30 ml of water wereadded at 0° C. and the mixture stirred for 15 minutes. The diethyl etherlayer was separated, washed with water, dried over magnesium sulfate,filtered, and concentrated in vacuo. The 1.6 grams of the4-chloropyridine produced were placed into a 3-necked flask anddissolved in 45 ml of ethylene glycol dimethyl ether (DME). Aftercooling to -70° C., 10 ml of 1.5 molar (M) solution of lithiumdlisopropyl amide (LDA) in cyclohexane were added over a period of 30minutes while maintaining the temperature below -60° C. Upon completionof the addition, the reaction mixture was stirred for an additional hourat -70° C. To this cooled mixture were then added 2.6 grams of4-bromopyridine-3-carboxaldehyde that was dissolved in 10 ml of DME. Thereaction mixture was stirred in a dry-ice bath for 2 hours and then leftat room temperature overnight. 35 ml of saturated ammonium chloridesolution were added to the reaction mixture, and the mixture was stirredfor 15 minutes at room temperature. The mixture was then extracted twicewith ethyl ether. The combined ether extracts were then washed withwater, dried over magnesium sulfate, filtered, and concentrated in vacuoto afford 2.9 g of the crude product as a viscous oil. This oil was thenchromatographed on a silica gel column using ethyl acetate as the eluantto afford 0.5 g of 1-(4-bromopyrid-3-yl)-1-(4-chloropyrid-3-yl)methanolas a waxy solid.

Example 2

Preparation of1-(4-bromopyrid-3-yl)-1-(4-chloropyrid-3-yl)-1-trimethylacetoxymethane(Compound No. 6)

0.4 grams of 1-(4-bromopyrid-3-yl)-1-(4-chloropyrid-3-yl)methanol weredissolved in 50 ml of tetrahydrofuran (THF) and cooled to 0° C. One gramof trimethylacetyl chloride was added followed by the portionwiseaddition of 0.5 grams of sodium hydride (60%) over a period of 15minutes. The reaction mixture was then allowed to warm to roomtemperature and then stirred overnight. 50 ml of a saturated ammoniumchloride solution were added and then this mixture was extracted twicewith ethyl ether. The combined ether extracts were washed with a 5%aqueous solution of potassium carbonate, dried over magnesium sulfate,filtered, and concentrated in vacuo to afford 0.5 g of1-(4-bromopyrid-3-yl)-1-(4-chloropyrid-3-yl)-1-trimethylacetoxymethaneas a waxy solid.

Example 3

Preparation of 1,1-bis-(2-chloro-4-trifluoromethylpyrid-3-yl)methanol(Compound No. 4)

To a magnetically stirred solution of 7.2 g of diisopropylamine in 100ml of dry THF at -70° C. under a nitrogen atmosphere were added 24 ml ofa 2.5M solution of n-butyl lithium in hexanes dropwise. After stirringfor 15 minutes, a solution of 10 g of 2-chloro-4-trifluoromethylpyridinein 20 ml of tetrahydrofuran (THF) was added dropwise. The light brownsolution was stirred at -73° C. for 45 minutes before 2 ml ofdimethylformamide (DMF) were added dropwise. After another 45 minutes,another 1.5 ml of DMF were added. The solution was stirred at -73° C.for 3 minutes more before 50 ml of a saturated ammonium chloride wereadded to quench the reaction. The reaction mixture was extracted with100 ml of ethyl ether. The ether layer was separated, washed with water,washed with saturated sodium chloride solution, dried over magnesiumsulfate, filtered, and concentrated in vacuo to afford 9.7 g of3-carboxaldehyde-2-chloro-4-trifluoromethylpyridine as an amber coloredoil.

To a solution of 2.2 g of diisopropylamine in 30 ml of THF at -73° C.under nitrogen atmosphere were added dropwise 7.3 ml of a 2.5M solutionof n-butyl lithium in hexanes. After 15 minutes, a solution of 3 g of2-chloro-4-trifluoromethylpyridine in 5 ml of THF was added dropwise.The resulting light brown solution was stirred at -73° C. for 1 hourbefore a solution of 3.5 g of3-carboxaldehyde-2-chloro-4-trifluoromethylpyridine in 5 ml of THF wasadded dropwise. After stirring for 30 minutes, the reaction mixture wasquenched with 10 ml of a saturated ammonium chloride solution. Thereaction mixture was extracted with 50 ml of ethyl ether. The etherlayer was separated, washed with water, washed with saturated sodiumchloride solution, dried over magnesium sulfate, filtered, andconcentrated in vacuo to afford 6.6 g of the crude prodduct as a viscousbrown oil. 2.4 g of this crude material were purified via chromatographyon a silica gel column using ethyl acetate-hexane (1:9) as the eluant toafford 1.6 grams of1,1-bis-(2-chloro-4-trifluoro-methylpyrid-3-yl)methanol as a yellowsolid.

Example 4

Preparation of 1,1-bis-(4-trifluoromethylpyrid-3-yl)methanol (CompoundNo. 9)

To a solution of 1.4 g of1,1-bis-(2-chloro-4-trifluoromethylpyrid-3-yl)methanol in 12 ml ofmethanol were added 0.8 g of magnesium oxide and 0.3 g of 5% palladiumon carbon. This mixture was then shaken on a Parr hydrogenationapparatus overnight under 50 psi of hydrogen. The palladium catalyst andmagnesium oxide were removed via filtration through dicalite, and themethanol filtrate was concentrated in vacuo to afford 1.6 of a yellowsolid. This solid was dissolved in 25 ml of methylene chloride. Themethylene chloride solution was washed with water, dried over magnesiumsulfate, filtered, and concentrated in vacuo to afford 0.93 g of1,1-bis-(4-trifluoromethylpyrid-3-yl)methanol as a yellow solid.

Example 5

Preparation of1,1-bis-(4-trifluoromethylpyrid-3-yl)-1-trimethylacetoxymethane(Compound No. 8)

To a mixture of 0.029 g of sodium hydride in 20 ml of a 1:1 solution ofbenzene and dimethylformamide were added 0.25 grams of1,1-bis-(4-trifluoromethylpyrid-3-yl)methanol. After the gas evolutionhad subsided, 0.14 grams of pivaloyl chloride were added. After stirringfor an hour at 50° C., the reaction mixture was partitioned between 25ml of water and 50 ml of ethyl ether. The ethyl ether layer was washedwith water, washed with a saturated sodium chloride solution, dried overmagnesium sulfate, filtered, and concentrated in vacuo to afford 0.24 gof the crude product as a light brown semisolid. This crude material wasthen purified via chromatography on a silica gel column using ethylacetate-hexane (1:3) as the eluant to afford 0.2 g of1,1-bis-(4-trifluoromethylpyrid-3-yl)-1-trimethylacetoxymethane as alight brown solid.

Example 6

Preparation of1,1-bis-(4-trifluoromethylpyrld-3-yl)-1-N,N-dimethylcarbamyloxymethane(Compound No. 7)

To a suspension of 0.029 g of sodium hydride in 2 ml of THF were added0.25 g of 1,1-bis-(4-trifluoromethylpyrid-3-yl)methanol. After the gasevolution had subsided, 0.13 g of dimethylcarbamyl chloride were added.After stirring for 20 minutes, the reaction mixture was partitionedbetween 25 ml of ethyl ether and 1 ml of water. The ether layer wasseparated, washed with a saturated sodium chloride solution, dried overmagnesium sulfate, filtered, and concentrated in vacuo to afford 0.26 gof1,1-bis-(4-trifluoromethylpyrid-3-yl)-1-N,N-dimethylcarbamyloxymethaneas a light brown solid.

Example 7

Preparation of1-(2-chloro-4-trifluoromethylpyrid-3-yl)-1-(6-chloro-4-trifluoromethylpyrimidin-5-yl)methanol(Compound No. 16)

To a solution of 1.03 g of diisopropylamine in 30 ml of THF at -73° C.under nitrogen atmosphere was added dropwise 3.6 ml of a 2.5M solutionof n-butyl lithium in hexanes. After 30 min, a solution of 1.24 g of6-chloro-4-trifluoromethylpyrimidine in 6 ml of THF was added dropwise.This solution was stirred at -70° C. for 20 min followed by dropwiseaddition of 1.42 g of3-carboxaldehyde-2-chloro-4-trifluoromethylpyridine in 5ml of THF. Afterstirring at -74° C. for 3.25 hours the mixture was quenched withsaturated ammonium chloride and extracted twice with 50 ml of ether. Thecombined organic layers were dried over magnesium sulfate, filtered, andconcentrated in vacuo to afford 2.58 g of a brown oil. The crude productwas purified via chromatography on silica gel using ethyl acetate-hexane(1:9) as the eluant to yield 0.391 g of1-(2-chloro-4-trifluoromethylpyrid-3-yl)-1-(6-chloro-4-trifluoromethylpyrimidin-3-yl)methanolas a viscous oil.

Example 8

Preparation of 1-(4-chloropyrid-3-yl)-1-(thien-2-yl)methanol (CompoundNo. 19)

15 g of 4-chloro pyridine hydrochloride were placed into 90 ml ofdiethyl ether in a 500 ml beaker equipped with a magnetic stirrer. 4.0 gof sodium hydroxide in 90 ml of water were added at 0° C. and themixture stirred for 15 minutes. The diethyl ether layer was separated,washed with water, dried over magnesium sulfate, filtered, andconcentrated in vacuo. The 10.3 g of the 4-chloropyridine produced wereplaced into a 3-necked flask and dissolved in 100 ml of ethylene glycoldimethyl ether (DME). After cooling to -70° C., 62 ml of 1.5M solutionof lithium diisopropyl amide (LDA) in cyclohexane were added over aperiod of 30 minutes while maintaining the temperature below -60° C.Upon completion of the addition, the reaction mixture was stirred anadditional hour at -70° C. To this cooled mixture were then added 10.7 gof 2-thiophenecarboxaldehyde. The reaction mixture was stirred in adry-ice bath for 2 hours and then left at room temperature overnight.100 ml of saturated ammonium chloride solution were added to thereaction mixture, and the mixture was stirred for 15 minutes at roomtemperature. The mixture was then extracted twice with ethyl ether. Thecombined ether extracts were then washed with water, dried overmagnesium sulfate, filtered, and concentrated in vacuo to afford thecrude product as a semi-solid. Trituration with hexane then affordedcrystals which were isolated through filtration. 14.5 g of1-(4-chloropyrid-3-yl)-1-(thien-2-yl)methanol were obtained.

Example 9

Preparation of1-(4-chloropyrid-3-yl)-1-(thien-2-yl)-1-trimethylacetoxymethane(Compound No. 20)

2.0 g of 1-(4-chloropyrid-3-yl)-1-(thien-2-yl)methanol were dissolved in100 ml of THF and the solution was cooled to 0° C. 3.2 g oftrimethylacetyl chloride were added followed by the portionwise additionof 1.0 g of sodium hydride (60%) over a period of 15 minutes. Thereaction mixture was allowed to warm to room temperature and thenstirred overnight. 100 ml of a saturated ammonium chloride solution wereadded, and then this mixture was extracted twice with ethyl ether. Thecombined ether extracts were washed with a 5% aqueous solution ofpotassium carbonate, dried over magnesium sulfate, filtered, and thenconcentrated in vacuo to obtain 2.7 g of crude product. This materialwas then purified via chromatography on a silica gel column using ethylacetatehexane (1:1) as the eluant to afford 1.9 g of1-(4-chloropyrid-3-yl)-1-(thien-2-yl)-1-trimethylacetoxymethane as anoil.

Example 10

Preparation of1-(4-chloropyrid-3-yl)-1-(thien-2-yl)-1-N,N-dimethylcarbamyloxymethane(Compound No. 21)

To a suspension of 0.5 g of sodium hydride (60%) in 100 ml of THF wereadded 2.0 g of 1-(4-chloropyrid-3-yl)-1-(thien-2-yl)methanol. After thegas evolution had subsided, 1.1 g of dimet:hylcarbamyl chloride wereadded. After stirring for 20 minutes, the reaction mixture waspartitioned between ethyl ether and water. The ether layer wasseparated, washed with a saturated sodium chloride solution, dried overmagnesium sulfate, filtered, and concentrated in vacuo to afford thecrude product. This material was then purified via chromatography on asilica gel column using methylene chloride-ethyl acetate (5:1) as theeluant to afford 1.8 g of1-(4-chloropyrid-3-yl)-1-(thien-2-yl)-1-N,N-dimethylcarbamyloxymethaneas a solid.

Example 11

Employing processes similar to those described above, additionalcompounds, as listed in Tables I, II and III, were prepared.

                  TABLE I                                                         ______________________________________                                         ##STR17##                                                                    Compound                                                                      No.     R.sup.1                                                                              R.sup.2                                                                             R.sup.3                                                                           R.sup.4                                                                           R         m   Y                                  ______________________________________                                        1       Cl     H     H   H   C(O)NHCH.sub.3                                                                          1   4-Cl                               2       Cl     H     H   H   C(O)NHCH.sub.3                                                                          0                                      3       Cl     H     H   H   C(O)N(CH.sub.3).sub.2                                                                   0                                      4       CF.sub.3                                                                             H     H   Cl  H         2   2-Cl,4-CF.sub.3                    5       Cl     H     H   H   H         1   4-Br                               6       Cl     H     H   H   C(O)C(CH.sub.3).sub.3                                                                   1   4-Br                               7       CF.sub.3                                                                             H     H   H   C(O)N(CH.sub.3).sub.2                                                                   1   4-CF.sub.3                         8       CF.sub.3                                                                             H     H   H   C(O)C(CH.sub.3).sub.3                                                                   1   4-CF.sub.3                         9       CF.sub.3                                                                             H     H   H   H         1   4-CF.sub.3                         10      CF.sub.3                                                                             H     H   H   C(O)NHCH.sub.2 CH.sub.3                                                                 1   4-CF.sub.3                         11      CF.sub.3                                                                             H     H   H   C(O)NHCH.sub.3                                                                          1   4-CF.sub.3                         ______________________________________                                    

                  TABLE II                                                        ______________________________________                                         ##STR18##                                                                    Compound                                                                      No.      R.sup.1                                                                              R.sup.2                                                                             R.sup.3                                                                           R.sup.4                                                                           R         p   Y                                 ______________________________________                                        12       CF.sub.3                                                                             H     H   Cl  H         2   4-OCH.sub.3,                                                                  6-Cl                              13       CF.sub.3                                                                             H     H   H   H         1   4-OCH.sub.3                       14       CF.sub.3                                                                             H     H   H   C(O)NHCH.sub.2 CH.sub.3                                                                 1   4-OCH.sub.3                       15       CF.sub.3                                                                             H     H   H   C(O)N(CH.sub.3).sub.2                                                                   1   4-OCH.sub.3                       16       CF.sub.3                                                                             H     H   Cl  H         1   4-CF.sub.3,                                                                   6-Cl                              ______________________________________                                    

                  TABLE III                                                       ______________________________________                                         ##STR19##                                                                    Compound                                                                      No.      R.sup.1                                                                             R.sup.2                                                                             R.sup.3                                                                           R.sup.4                                                                           R         Z   m   Y                              ______________________________________                                        17       Cl    H     H   H   C(O)N(CH.sub.3).sub.2                                                                   O   0                                  18       Cl    H     H   H   C(O)NHCH.sub.3                                                                          O   0                                  19       Cl    H     H   H   H         S   0                                  20       Cl    H     H   H   C(O)C(CH.sub.3).sub.3                                                                   S   0                                  21       Cl    H     H   H   C(O)N(CH.sub.3).sub.2                                                                   S   0                                  22       Cl    H     H   H   H         N   1   1-CH.sub.3                     ______________________________________                                    

HERBICIDAL SCREENING TESTS

Compounds listed in the foregoing tables were tested for herbicidalactivity by various methods and at various rate of application. Theresults of some of these tests are given below. As one skilled in theart is aware, the results obtained in herbicidal screening tests areaffected by a number of factors that are not readily controllable.Environmental conditions, such as amount of sunlight and water, soiltype soil pH, temperature and humidity, are examples of such facters.Other factors which can affect test results are the depth of plantingand the application rate of the herbicide, as well as the nature of thecrops being tested. Results will also vary from crop to crop and withinthe crop varieties.

PRE-EMERGENCE HERBICIDAL SCREENING TEST

On the day preceding treatment, seeds of several different weed specieswere planted in sandy loam soil at a depth of 0.5 inch (1.3 cm) inindividual rows using one species per row across the width of a flat.The soil was fortified with 17--17--17 fertilizer (N--P₂ O₅ --K₂ O) on aweight basis and pasteurized. The weeds planted were wild oat (Avenafatua) (AVEFA), barnyardgrass (Echinochloa crusgalli) (ECHCG), greenfoxtail (Setaria viridis) (SETVI), velvetleaf (Abutilon theophrasti)(ABUTH), morningglory species (Ipomoea spp.) (IPOSS), wild mustard(Sinapsis arvensis) (SINAR) and yellow nutsedge (Cyperus esculentus)(CYPES). Plant densities ranged from 3 to 25 plants per row, dependingupon the size of the plants.

Solutions of the test compounds were made by weighing out an appropriateamount of the test compound, for example 74.7 mg for an application rateof 4.0 kg/ha or 18.8 mg for an application rate of 1.0 kg/ha, into a 60ml widemouth bottle, then dissolving the compound in 7.0 ml acetonecontaining 1% Tween 20® (polyoxyethylene sorbitan monolaurateemulsifier) and then adding 7 ml of deionized water to reach a 14 mlfinal volume. Tween 20® content was 0.5% v/v of the final spray volume.Additional solvents, not exceeding 2 ml, were used if needed to dissolvethe compound.

The soil surface was sprayed inside an enclosed linear spray table. Theflats were sprayed with the spray solution calibrated to deliver 748L/ha. The application rate was between 0.9 and 4.0 kg/ha.

The flats were placed into a greenhouse at 21°-29° C. and watered dailyby sprinkling. The degree of weed control was visually assessed andrecorded 17-21 days after treatment, as percentage control compared tothe growth of the same species of the same age in an untreated checkflat.

The results of such pre-emergent testing are summarized in Table IVbelow.

POST-EMERGENCE HERBICIDAL EVALUATION

The soil was prepared and seeded with the same species and methodologydescribed for the pre-emergence test. The flats were placed in thegreenhouse at 21°29° C. and watered by sprinkling. The seeds of the weedspecies were planted 10-12 days before treatment. In general, grasseswere sprayed at a 3 to 4 leaf stage and broadleaves at a 1 to 2 leafstage. Watering of the treated flats was confined to the soil surfaceand not to the foliage of the germinated plants. The degree of weedcontrol was visually assessed and recorded 17-21 days after treatment,as percentage control compared to the growth of the same species in anuntreated check flat of the same age.

The results of such post-emergent testing are summarized in Table Vbelow.

The percent control is the total injury to the plants due to allfactors, including inhibited germination, killing of the plant tissueafter emergence, stunting, malformation, chlorosis and other types ofinjury. The control ratings vary from 0 to 100 percent, where 0represents no effect with growth equal to the untreated control, and 100represents complete kill.

                                      TABLE IV                                    __________________________________________________________________________    Pre-Emergent - Testing                                                        COMPOUND                                                                      NO.    KG/HA                                                                             AVEFA                                                                             ECHCG                                                                             SETVI                                                                             ABUTH                                                                              IPOSS                                                                             SINAR                                                                             CYPES                                     __________________________________________________________________________    1      4.0 80  100 100 10   100 10  50                                        2      4.0 0   0   10  0    0   0   0                                         3      4.0 0   5   15  0    0   0   0                                         4      4.0 5   25  60  10   10  10  0                                         6      4.0 10  100 100 5    100 20  70                                        7      1.0 98  100 100 98   95  85  100                                       8      1.0 98  100 100 100  98  85  75                                        9      1.0 30  100 80  0    5   0   70                                        10     1.0 98  100 100 95   95  80  100                                       12     1.0 0   0   10  10   0   0   0                                         13     0.9 0   0   0   0    10  0   0                                         14     1.0 98  100 100 85   98  75  80                                        17     4.0 0   0   10  0    0   0   0                                         18     4.0 0   0   15  0    0   0   0                                         19     4.0 0   0   5   10   0   0   0                                         20     4.0 0   15  50  0    0   10  0                                         21     4.0 0   10  40  0    0   0   0                                         __________________________________________________________________________

                                      TABLE V                                     __________________________________________________________________________    Post-Emergent - Testing                                                       COMPOUND                                                                      NO.    KG/HA                                                                             AVEFA                                                                             ECHCG                                                                             SETVI                                                                             ABUTH                                                                              IPOSS                                                                             SINAR                                                                             CYPES                                     __________________________________________________________________________    1      4.0 15  95  95  40   85  15  60                                        2      4.0 0   0   5   0    20  10  0                                         3      4.0 0   0   10  10   10  5   0                                         4      4.0 0   0   0   0    5   5   0                                         6      4.0 10  60  50  90   90  25  10                                        7      1.0 50  90  80  90   90  25  70                                        8      1.0 10  50  75  80   90  20  5                                         9      1.0 0   10  0   5    25  0   0                                         10     1.0 50  85  90  95   95  50  50                                        12     1.0 0   0   0   5    0   0   0                                         13     0.9 0   0   0   0    10  5   0                                         14     1.0 0   5   15  70   60  5   10                                        17     4.0 0   0   5   5    5   5   0                                         18     4.0 0   0   0   0    0   0   0                                         19     4.0 0   0   0   10   15  15  0                                         20     4.0 0   10  10  5    30  5   0                                         21     4.0 5   5   10  20   20  60  0                                         __________________________________________________________________________

The results above illustrate the preemergent and postemergent efficacyof the present compounds against a variety of grass, broadleaf andperennial weed species.

Although the invention has been described with reference to preferredembodiments and examples thereof, it is not intended that the presentinvention be limited to only those described embodiments. Thedescription of the preferred embodiments contained herein is intended inno way to limit the scope of the invention. As will be apparent to aperson skilled in the art, modifications and adaptations of theabove-described invention will become readily apparent without departurefrom the spirit and scope of the invention, the scope of which isdefined and circumscribed by the appended claims.

What is claimed is:
 1. A compound of the formula ##STR20## wherein: Aris a substituted or unsubstituted pyrimidinyl group wherein thesubstituents on the pyrimidinyl ring may be the same or different andare independently selected from halogen, C₁ -C₆ alkyl, C₁ -C₆ haloalkyl,C₁ -C₆ alkoxy, C₂ -C₆ alkenyl, C₂ -C₆ alkynyl, C₁ -C₆ alkylcarbamylthio,mecapto, C₁ -C₆ haloalkoxy, nitro, cyano, hydroxy thiocyano, (C₁-C₆)alkoxy (C₁ -C₆)alkyl, --S(O)_(k) --R¹⁰ or N(R¹¹)(R¹²);R¹ is halogen,C₁ -C₆ alkyl, C₂ -C₆ alkenyl, C₂ -C₆ alkynyl, nitro, cyano, hvdroxy,thiocyano, --N(R¹¹)(R¹²), C₁ -C₆ halo alkyI, C₁ -C₆ alkoxy, C₁ -C₆haloalkoxy, (C₁ -C₆)alkoxy-(C₁ -C₆)alkyl, halo(C₁ -C₆)-alkoxy-(C₁-C₆)alkoxy, --C(X)--R¹⁰ or --S(O)_(k) --R¹⁰ ; R², and R³ are eachindependently hydrogen, halogen, C₁ -C₆ alkyl, C₂ -C₆ alkenyl, C₂ -C₆alkynyl, nitro, cyano, hydroxy, thiocyano, --N(R¹¹)(R¹²), C₁ -C₆ haloalkyl, C₁ -C₆ alkoxy, C₁ -C₆ haloalkoxy, (C₁ -C₆)alkoxy-(C₁ -C₆)alkyl,halo(C₁ -C₆)-alkoxy-(C₁ -C₆) alkoxy, --C(X)--R¹⁰ or --S(O)_(k) --R¹⁰ ;R4 is hydrogen, halogen, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl,nitro, hydroxy, thiocyano, --N(R11) (R12), C1-C6 halo alky, C1-C6alkoxy, C1-C6 haloalkoxy, halo(C1-C6) alkoxy- (C1-C6) alkoxy,or--S(O)k--R10; X is oxygen or sulfur; R is hydrogen, hydrocarbyl,hydrocarbyl substituted with one or more of halogen or C₁ -C₆ alkoxy oris of the formula --C(O)--C(O)--R⁶, --S(O)₂ --R⁶, or --P(Q)(R¹¹)(R¹²) orSi(R¹³)(R¹⁴)(R¹⁵), wherein:Q is oxygen or sulfur; R⁶ is hydrocarbyl,substituted hydrocarbyl, hydrocarbyloxy, substituted hydrocarbyloxy,hydrocarbyl-S-, substituted hydrocarbyl-S- or is of the formula--N(R⁷)(R⁸); wherein R⁷ and R⁸ are each independently hydrogen,hydrocarbyl, substituted hydrocarbyl, hydrocarbyloxy, substitutedhydrocarbyloxy, pyridyl, furyl, thienyl, (C₁ -C₆)alkoxycarbonyl(C₁-C₆)alkyl, hydroxycarbonyl(C₁ -C₆)alkyl, or N(R⁹)(R¹⁰) wherein R⁹ andR¹⁰ are each independently hydrogen, C₁ -C₆ alkyl or phenyl; or R⁷ andR⁸ together with the nitrogen to which they are bound form an aziridine,piperazine, morpholine, thiomorpholine, thiomorpholine 1-oxide,thiomorpholine 1,1-dioxide, hexamethyleneimine, piperidine orpyrrolidine ring, any of which may be optionally substituted with C₁ -C₆alkyl; R¹¹ and R¹² are each independently C₁ -C₆ alkyl, C₁ -C₆ alkylthioor C₁ -C₆ alkoxy; R¹³, R¹⁴ and R¹⁵ are each independently C₁ -C₆ alkyl,C₁ -C₆ alkoxy, C₁ -C₆ haloalkyl, aryl or arylalkyl; k is 0, 1 or 2; andn is 0 or 1; wherein hydrocarbyl is selected from C₁ -C₁₂ alkyl, C₃ -C₁₂cycloalkyl, C₂ -C₁₂ alkenyl C₁ -C₂ alkynyl, aryl, aryl(C₁ -C₁₂)alkyl,(C₁-C₁₂)alkylaryl, C₂ -C₁₂ alkeynyl aryl or (C₂ -C₁₂)alkynyl aryl;substituted hydrocarbyl is wherein one of said hydrocarbyl groups issubstituted by one or more groups selected from halogen, (C₁ -C₄)alkoxy, (C₁ -C₄) alkyl-S(O)_(k) -, nitro, cyano, carboxy, and salts,amides and esters thereof, (C₁ -C₄) alkanoyl and phenyl optionallysubstitutited by one or more (C₁ -C₄) alkyl, (C₁ -C₄)alkoxy, (C₁ -C₄)alkyl-S(O)_(k) -, nitro, fluorine, chlorine, bromine, cyano, or CF₃groups; or an agriculturally acceptable salt thereof.
 2. A compound asdefined in claim 1, or an agriculturally acceptable salt thereof, havingthe formula ##STR21## wherein X, R, R¹, R², R³, R⁴ and n have the samemeanings as set forth in claim 1;p is 0, 1, 2 or 3; and when p is not 0,each Y is independently hydrogen, halogen, C₁ -C₆ alkyl, C₁ -C₆haloalkyl, C₁ -C₆ alkoxy, C₂ -C₆ alkenyl, C₂ -C₆ alkynyl, C₁ -C₆alkylcarbamylthio, mercapto, C₁ -C₆ haloalkoxy, nitro, cyano, hydroxy,thiocyano, (C₁ -C₆)-alkoxy-(C₁ -C₆)alkyl, --S(O)_(k) --R¹⁰ or--N(R¹¹)(R¹²), wherein k, R¹⁰,R¹¹ and R¹² have the same meanings as inclaim
 1. 3. A compound as defined in claim 1, wherein X is oxygen and Ris hydrogen.
 4. An herbicidal composition comprising an herbicidallyeffective amount of a compound according to claim 1, or anagriculturally acceptable salt thereof, and an agriculturally acceptablecarrier therefor.
 5. An herbicidal composition comprising anherbicidally effective amount of a compound according to claim 2, or anagriculturally acceptable salt thereof, and an agriculturally acceptablecarrier therefor.
 6. An herbicidal composition comprising anherbicidally effective amount of a compound according to claim 3, or anagriculturally acceptable salt thereof, and an agriculturally acceptablecarrier therefor.
 7. A method for controlling undesirable vegetationcomprising applying to an area where control is desired an herbicidallyeffective amount of a compound according to claim 1, or anagriculturally acceptable salt thereof.
 8. A method for controllingundesirable vegetation comprising applying to an area where control isdesired an herbicidally effective amount of a compound according toclaim 2, or an agriculturally acceptable salt thereof.
 9. A method forcontrolling undesirable vegetation comprising applying to an area wherecontrol is desired an herbicidally effective amount of a compoundaccording to claim 3, or an agriculturally acceptable salt thereof.